Machine for winding a fibrous mat on itself

ABSTRACT

A machine winds a fibrous mat on itself after compressing it. The winding machine has two bands which each embrace about half the circumference of the roll being formed. The machine also includes a plate intended to keep the mat compressed. This plate and, if appropriate, a device for causing compression of the mat are movable and advance downstream as the fibrous mat is wound. In a variation, the compression device is fixed and the plate is lengthened.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to the techniques of compressing and then windingfibrous mats in order to make it possible to package and condition themuntil they reach their place of use. Flexible fibrous mats, especiallythose which consist of glass wool or rock wool and are intended forinsulation, are usually wound on themselves in a very close-packedmanner, so as to avoid them occupying too large a volume while beingtransported. The higher the compression ratio of the mat, the lesscostly are transport and storage.

2. Description of the Related Art

In general, the production lines operate continuously and deliver matsof uninterrupted length. These mats are cut in order to form rolls, thewidth and length of which correspond to the user's requirements. On theproduction lines for mats of insulating wool, there are winding machineswhich operate in a more or less automated manner.

In order to perform their functions, these machines must have some basiccharacteristics. They must compress the wool mats as much as possible inthe same way over their entire length, but they must also avoid damagingthe fibre and binder forming the insulating mat.

Moreover, it is important for all the operations to take place atsufficient speed to be compatible with the speed of travel of the mat.This is a particularly important point as regards modern lines where itis often desirable to increase the production capacity. For thispurpose, the number of upstream units producing glass or rock fibres isincreased, all these units successively feeding the same mat, the speedof travel of which depends, all else being equal, on the number ofmachines upstream.

In order to reduce transport costs, high compression ratios must beachieved, without the fibrous mat being damaged.

The rolls of mineral fibre mats, which it is possible to obtain withwinding machines of the prior art, are limited, in the case of specificmasses of 8 to 10 kg/m³, to compression ratios of less than 7/1, ifcompression is carried out in a single operation, and to ratios ofbetween 6 and 8/1, with methods comprising two mechanical steps or onemechanical step and one vacuum step.

Existing winding machines are of two types: either the elements betweenwhich winding takes place are essentially plane elements or windingtakes place within a substantially circular cavity.

Some of the winding machines which use two plane conveyor belts forminga dihedron with an aperture of, for example, 60° and within which thewinding of the fibrous mat takes place, employ compression plates.

Thus, European Patent Application Serial No. 672 014 employs a doubledevice both for causing the compression of the mat and for makingwinding easier. On the one hand, a conveyor band and, on the other hand,a plate are used. The conveyor band is not, as is customary, carried anddriven by two rollers, but the second roller is replaced by a cylinderof small diameter, thus making it possible to introduce the conveyor along way between the last turn and the mat portion following the latter.The device comprises, moreover, a plate which ensures that the mat isboth compressed and held in the compressed state.

These two elements, namely the < tapered > conveyor and plate, arerigidly connected and move away upstream of the approaching mat as theroll increases in diameter.

European Patent Application Serial No. 374 985 has likewise provided aplate associated with a band conveyor. Its function is merely tomaintain the compression produced by the conveyor band which itsucceeds. Here too, the assembly is associated rigidly and advancesupstream when the roll being formed increases in size.

European Patent No. 551 228 describes a winding machine intended forwinding a fibrous mat on itself. It is of the type which employs twobelts surrounding the entire roll being formed; it comprises means forcompressing the fibrous mat, such as two plane band conveyors, whichapproach one another, thereby forming a dihedron of small aperture. Theessential feature of this winding machine is two belts of which oneembraces substantially half the circumference of the roll being formedand the other a large part of the rest. The winding speed and thecompression ratio possible without the fibrous mats being damaged areexcellent. It became clear, however, that it was still possible toimprove the operation of the preceding winding machine.

As described in European Patent No. 551 228, the winding machine has, infact, an exemplary embodiment in which the state of compression of thefibrous mat, compressed by the two band conveyors mentioned above, ismaintained by means of a plate. In fact, the mat is compelled to slideunder the plate which is parallel to the conveyor supporting the alreadycompressed mat. Among the variants of the prior winding machine whichhave been presented, the one comprising the sliding plate is animprovement when compared with the other variants. However, this platefully performs its function only at the commencement of winding; whenthe roll increases in size, the distance between the end of the plateand the already formed first turn of the roll increases, and this mayallow some decompression of the mat.

The technique of the invention was developed in order to overcome thisslight disadvantage.

SUMMARY OF THE INVENTION

One object of the invention is to provide fibrous mats which are woundon themselves with high compression ratios and which, on decompression,recover their original characteristics.

One object of the invention is also to provide a winding machine whichdoes not damage the fibers and binder of the fibrous mat in any wayduring compression.

The invention relates to winding machines of the type which, forpressing on the fibrous roll, employs either one free belt or two beltswhich form a kind of circular cavity around the roll;

The invention provides a winding machine for winding a fibrous mat onitself, the said winding machine comprising, in particular, means forcompressing the mat in translational motion, with a device, such as aplate, for keeping the mat compressed, as well as two belts, of whichone embraces substantially half the circumference of the roll beingformed and the other a substantial part of the other half, in whichwinding machine the device keeping the mat compressed is movable andcapable of being displaced downstream as the roll is wound.

The solution of the invention makes it possible to benefit from theeffect of the plate both at the commencement and at the end of thewinding operation.

In a variant, the compression means, located on the same side as thedevice keeping the mat compressed, is likewise movable and capable ofbeing displaced downstream as the roll is wound, and, preferably, thecompression means and the device for keeping the mat compressed areintegral with one another.

BRIEF DESCRIPTION OF THE DRAWINGS

The figures and the following description will make it possible tounderstand the operation and advantages of the invention.

FIG. 1 shows the device for maintaining compression and the associatedcompression means in the upstream position.

FIG. 2 shows these same elements in the downstream position.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1, the roll 2 of the compressed fibrous mat 1 begins to beformed the belts 3 and 4 driven and/or guided by the fixed rollers 5 and6 and the movable rollers 7 and 8. The operation of the winding machineof FIGS. 1 and 2 is explained fully in European Patent No. 551 228. Thefibrous mat 1 is compressed as a result of the paired action of two beltconveyors, the lower conveyor 9 driven and/or guided by the roller 10(this assembly not changing its position during winding) and the upperconveyor 11 driven and/or guided by the roller 12. This upper assembly,which forms a means of compressing the fibrous mat, may be movable, onthe one hand, perpendicularly to the mat 1 in order to modify its finalthickness, and, on the other hand, in the direction of displacement ofthe mat 1 in order to make it easier for the latter to be wound.

FIG. 1 also illustrates a plate 13 which forms an example of the devicefor keeping the mat 1 in its compressed state. This plate 13 ispreferably located immediately downstream of the roller 12 which is atthe end of the upper conveyor 11, so as to avoid intermediatedecompression of the mat.

While the compressed mat 1 is being wound, its center moves away fromthe fixed roller 6, while its curvature decreases. The result of thisdouble phenomenon is that this same fixed roller 6 moves away from thecontact line 14 between the last turn being formed and the precedingturn. The invention therefore provides for displacing the plate 13 inorder to bring it nearer to this contact line 14.

FIG. 2 shows the situation of the various elements of the windingmachine after the displacement of the plate 13 following the winding ofthe compressed mat.

The figure illustrates the plate 13 and the upper conveyor 11 as beingintegral, that is to say that they are displaced simultaneouslydownstream during winding.

The scope of the invention is not exceeded if, while the upper conveyor11 remains fixed, only the plate 13 approaches the roll being formed. Inthis case, it will have been possible to avoid decompressing thecompressed mat 1 by lengthening the plate 13, one end of which remainsin the vicinity of the roller 12, while the other end remains near thecontact line 14. This plate 13 of variable length consists, for example,of two parts which partially overlap and slide relative to one another.

What is claimed is:
 1. Winding machine for winding a fibrous mat onitself, said winding machine comprising:a compression device which actsto compress the mat in translational motion, with a plate for keepingthe mat compressed, and two belts of which one embraces substantiallyhalf the circumference of a roll being formed and the other asubstantial part of the other half, wherein the plate keeping the matcompressed is movable and capable of being displaced downstream as theroll is wound, said plate having two parts which partially overlap andslide relative to one another.
 2. Winding machine according to claim 1,wherein the compression device, located on the same side as the platekeeping the mat compressed, is likewise movable and capable of beingdisplaced downstream as the roll is wound.
 3. Winding machine accordingto claim 2, wherein the compression device and the plate for keeping themat compressed are integral with one another.
 4. Winding machineaccording to claim 1, wherein the compression device is fixed, andfurther wherein the plate for keeping the mat compressed is lengthenedas the roll is wound.
 5. Winding machine according to claim 1, whereinthe compression device and the plate for keeping the mat compressed aredisplaced simultaneously downstream during winding.